I have a tricky problem that I initially tried to ask the manufacturer of my laptop but has failed to get an answer to.

I have a Lenov Thinkpad Yoga laptop with a i7-4600U CPU and HD Graphics 4400 running windows 8.1 and a dock for it called Lenovo OneLink Pro Dock.

The Dock is said to do just graphics passthrough from the Laptop to the DisplayPort on the dock and is said to support DisplayPort 1.2

I'm trying to connect 2 displays (Dell U2515H with resolution 2560x1440) to this dock using "daisy chaining" to be able to use 2 displays with the setup.

Both displays are recognized by windows 8.1 if I go into the "Screen resolution" window.

The problem comes with the resolution, when one of the displays are running 2560x1440 the other display can only use a resolution of 1024x768, if I go back into the "Screen resolution" window, I can select 2560x1440 in the resolution list but when I try to click "OK" or "Apply" I get the response that the display settings can't be saved.

Same thing if I go into "Advanced settings" and click "List all modes", selects the "2560x1440 60Hz" mode and clicks "Apply", now the response is that something went wrong with the graphics driver.

If I right click on the desktop and select the Intel alternative "Graphic option>Resolution>2560x1440" then nothing happens, the display just stays at 1024x768.

I have tried to update the driver to version 10.18.14.4080 and installed the latest driver for the displays but without any success.

Lenovo support don't really know what to do next and I wanna get this setup working.

Does anyone have an idea to what the problem is or maybe any tips on how I can debug further?

Using the software to set the resolution just opens the windows 8.1 screen resolution window so there is nothing special to it.

The manual say DP 2560x1600 but according to the sales documentation it sais "Full Dual video output is supported on ThinkPads with DisplayPort 1.2" which my laptop supports, the resolutions listed in the manual is only if you use both DP and DVI.

When talking to Lenovo support they themself think it should be possible to do but they can't say why it's not working.